CELL PHYSIOLOGY EXAM | QUESTIONS & ANSWERS (VERIFIED) | LATEST UPDATE | GRADED A+

1 CELL PHYSIOLOGY EXAM | QUESTIONS & ANSWERS (VERIFIED) | LATEST UPDATE | GRADED A+ How big is a typical human cell and can you see it with the naked eye? Correct Answer: 10 um and no Why is a cell roughly 10 um? Correct Answer: This size allows the cell to effectively communicate with its environment through its plasma membrane. What would happen if a cell got bigger than 10um? Correct Answer: cell's membrane would not be able to efficiently communicate with its environment due to the increase in size. What are the 2 major classes of cells? Correct Answer: Solar cells & gametes. What is the lipid to protein ratio (in%) that makes up a cell membrane and how does this relate to weight? Correct Answer: 98% lipid 2% protein but the weight is 50/50 because proteins are big heavy molecules 2 What type of fluid does the e (extracellular) face of the cell face? Correct Answer: Interstitial fluid What type of fluid does the p face of the cell face? Correct Answer: Intracellular fluid and p is referring to the cytoplasm or inside of the cell What can sugars in the extracellular portion be attached to? Correct Answer: Phospholipids or proteins If a sugar is attached to a lipid what is it called? Correct Answer: Glycolipids If a sugar is attached to a protein what is it called? Correct Answer: Glycoprotein What are glycolipids and glycoproteins collectively referred to as? Correct Answer: Glycoxyl What are 2 major cell classes? Correct Answer: body cells and sex cells (gametes) Are gametes haploid or diploid? 3 Correct Answer: haploid (1n) Are body cells haploid or diploid? Correct Answer: diploid (2n) What is a composite cell? Correct Answer: typical cell that contains all components that a cell could potentially have If RBCs don't have a nucleus or organelles how do they stay alive? Correct Answer: Glycolysis White blood cells (B cells) have a lot of rough ER in their nucleus, why is this? Correct Answer: they make a lot of proteins and supply those to other cells What 3 proteins make up the cytoskeleton & what is their job? Correct Answer: microfilaments (actin filaments), intermediate filaments, microtubules and their job is to support the body of the cell & they give the cell their shape Are cilia and microglia projections of the cell or project off the cell? Correct Answer: Projections of the cell or extensions of the cell What is the smooth ER responsible for? 4 Correct Answer: making lipids and breaking down toxins What is the ER responsible for? Correct Answer: Making & Moving protiens (secretion) when looking at a cell membrane, what direction will the e and p face always be? Correct Answer: E- top P-bottom T or F? Glycoproteins & glycolipids are only found the the e face of the cell? Correct Answer: T What are the identify markers of the cell, found on the e face of their cell membranes? Correct Answer: Glycolipids and glycoproteins, these are very specific to the cell Why is cholesterol a critical component of the plasma membrane? Correct Answer: Support and stabilization Each protein that goes through the membrane has what 2 kinds of faces? Correct Answer: E face Moya T & P face moya T What does the E face moya T interact with? Correct Answer: Ligands and carbs 5 What does the P face moya T interact with? Correct Answer: Enzymes What are identify markers on the cell membrane and what is their significance? Correct Answer: Glycolipids & glycoproteins, they serve as identity markers of the cell What percent of the 98% plasma lipid membrane are phospholipids and what % is cholesterol ? Correct Answer: 75% phospholipids & 20% cholesterol What is an amphipathic molecule? Correct Answer: A molecule that has a hydrophilic and hydrophobic end. Example: phospholipids What do ribosomes do? Correct Answer: make proteins How does cholesterol resist phase? Correct Answer: By providing structure of the cell membrane during times when the membrane phospholipids get warm & want to move away from one another 6 What are transmembrane proteins & how does their material match that of the cell membrane? Correct Answer: They are proteins that are integrated into the cell membrane. Their middle material is hydrophobic like the lipid belayer of the cell membrane, & their superior & inferior region is hydrophilic like the polar heads of the cell membrane. If a protein has 20 AA that are hydrophobic than it is almost guaranteed to be what kind of membrane protein? Correct Answer: Transmembrane (integral) protein Where are peripheral membrane proteins found on the cell membrane and why are the vast majority of them found on the p face of the cell? Correct Answer: they are found on either the e face or the p face of the membrane and do not span across the entire membrane. The majority are associated with the p face of the cell doing enzymatic activity What are the structural classes of membrane proteins? Correct Answer: integral (transmembrane) proteins and peripheral proteins Why are functional proteins necessary for multicellular organisms? Correct Answer: functional proteins are necessary for bringing 2 plasma membranes together, each one from a different cell. 7 When functional proteins bring 2 cell membranes together, do the proteins or the cell membranes touch? Correct Answer: Proteins What type of fluid is between 2 cell membranes that are brought together by functional proteins? Correct Answer: Interstitial What are macrophages? Correct Answer: They are big eaters that engulf debris, foreign materials, bacteria, and viruses. What are the 2 classes of membrane proteins? Correct Answer: Structural and functional classes What are recognition proteins & what is the purpose of glycoproteins found on them? Correct Answer: They are sugars that stick off the surface of the cell, they help identify the cell & prevent attack by immune system. What class of protein membranes are enzymes found in & how are they arranged on the cell membrane? Correct Answer: They are apart of the functional class of membrane proteins & they are found in the membrane. 8 What is the purpose of enzyme proteins found on the cell membrane? Correct Answer: Catalyze intracellular or extracellular reactions Do the majority of enzyme proteins face the e or p face of the cell? Correct Answer: P face Are receptor proteins a functional or structural membrane protein? Correct Answer: Functional Are receptor proteins transmembrane proteins & what face of the cell is it facing? Correct Answer: Yes & e face What happens to the receptor when a ligand binds to it? Correct Answer: It undergoes a conformational change Is a carrier protein a functional or structural membrane protein & what causes it to undergo a conformational change? Correct Answer: Functional & when solutes bind to it What is the purpose of a leak channel and is it a structural or functional membrane protein? 9 Correct Answer: Allows continuous flow of ions across the cell membrane and its a functional membrane protein What is the purpose of a gated channel and is it a structural or functional protein? Correct Answer: It can open or close to allow for ion movement and its a functional protein? What are the 3 mechanisms by which ion gated channels are opened? Correct Answer: Mechanically, voltage-gated, and ligand-gated Membrane transport requires 2 things, what are they? Correct Answer: Pathway & an energy source What is the difference between active and passive transport? Correct Answer: Passive is referring to the energy of concentration gradients & active is referring to the use of energy to pump against the concentration gradient What are membrane carbohydrates? Correct Answer: glycoproteins and glycolipids What are the factors that affect diffusion? Correct Answer: concentration, temperature, distance, size, electrical forces 10 What is the collective name of glycoproteins + glycolipids? Correct Answer: Glycocalyx Would glycoproteins & glycolipids be antigens or antibodies? Correct Answer: Antigens because they are identify markers What system makes antibodies and what do they target? Correct Answer: Lymphatic system or immune system & they target antigens on the cell What molecules can get through the membrane? Correct Answer: Non-polar small molecules, fatty acids, gases, & steroids What does it mean for diffusion to be a decrementing process? Correct Answer: The gradient gets weaker & weaker as solutes move through it Why is distance arguably the most important factor affecting diffusion & how what value (in microns) sets the standard between the cell & a blood vessel? Correct Answer: Because if you move a cell any further than 20 microns ( 2 cell links) away from a blood vessel it can't properly diffuse nutrients and waste between itself & the blood vessel. How does Brownian motion drive concentration gradients? 11 Correct Answer: Through entropy, chemicals will move from areas of high concentration to areas of low concentration or down its concentration gradient What is osmosis? Correct Answer: diffusion of water down its concentration gradient What does it mean for a solution to have low osmotic potential? Correct Answer: The solution has a lot of solute, therefore water will not want to diffuse across the membrane What does it mean for a solution to have high osmotic potential? Correct Answer: The solution does not have a lot of solute, therefore water will want to diffuse across the membrane T or F? Blood pressure & blood volume are directly proportional? Correct Answer: T How are cells in an isotonic environment? Correct Answer: They have roughly the same amount of solutes on the inside and outside of the cell = same amount of water coming in & going out = no net movement of water = cell not changing its shape What does it mean when a cell is in a hypotonic environment? 12 Correct Answer: The intracellular fluid has more solutes than the interstitial (extracellular) fluid, therefore water will flow in & cause the cell to swell & potentially burst What does it mean when a cell is in a hypertonic environment? Correct Answer: The extracellular fluid has more solutes than the intracellular fluid, therefore water will flow out of the cell & the cell will shrink What is it called when a cell shrinks or shrivels up? Correct Answer: Cremate What does hypotonic mean? Correct Answer: less solute, more water What does hypertonic mean? Correct Answer: more solute, less water What is facilitated diffusion & what types of molecules would use this? Correct Answer: the diffusion of large & polar molecules down their concentration gradient & are facilitated by protein channels What types of proteins channels are used in facilitated diffusion? Correct Answer: Channels, gated channels & carrier proteins 13 Explain the difference in mechanisms between a uniporter, symporter, and antiporter? Correct Answer: A uniporter transports solutes in one direction, a symporter transports 2 or more solutes in the same direction, & a antiporter transports 2 or more solutes in opposite directions Why are symporters & antiporters collectively called cotransporters? Correct Answer: They both transport 2 or more solutes Does the majority of water move through the phospholipid bilayer or aquaporins (water channels) Correct Answer: Aquaporins How do GLUT transporters facilitate the transport of glucose? Correct Answer: Glucose binds & causes a conformational in the protein & then that protein lets glucose go do its new shape Where are GLUT 4 transporters located & what are they sensitive to? Correct Answer: Located in fat & skeletal muscles cells & they are sensitive to insulin Where are GLUT 1 transporters located? Correct Answer: On all cells in the body 14 When glucose enters a myocyte it's converted into G6F and then glycogen, why is this? Correct Answer: To maintain the glucose concentration gradient. What is primary active transport? Correct Answer: Direct use of ATP to move molecules across the membrane AGAINST their concentration gradient How many Na+ and K+ ions does the sodium potassium pump at once? Correct Answer: 3 Na+ out and 2 K+ in T or F? 1/3 of all body energy is used to run the Na+/K+ pump? Correct Answer: T How does secondary active transport differ from primary active transport? Correct Answer: Secondary active transport utilizes a concentration gradient as its energy source & primary active transport utilizes ATP as its energy source Compare & contrast GLUTS and SGLTS and include how glucose is utilized Correct Answer: GLUTS are the primary mechanism by which glucose gets into the cells (fat & muscle cells) & SGLTS is the primary way that glucose gets into the body or blood through the small intestine How do SGLTS carry glucose across it's concentration gradient? 15 Correct Answer: The SGLT transporter opens, allowing Na+ to flow down it's concentration gradient & dragging glucose along with it. Glucose will be flowing against it's concentration gradient because there is more glucose inside of the cell then outside Where are SGLT1s located? Correct Answer: Intestine Where are SGLT2s located? Correct Answer: Kidney What does the pump-leak model show? Correct Answer: the relationship & significance between active & passive transport & how ions can be recycled to fuel other pathways What is vesticular transport? Use endocytosis & exocytosis in your answer Correct Answer: How the cell membrane forms or deforms vesicles to move material inside or outside of the cell. When the membrane brings in material to the cell it will form a vesicle (endocytosis) and when the membrane moves material out of the cell the vesicle will fuse back with its cell membrane (exocytosis) What are the 3 forms of endocytosis? Correct Answer: pinocytosis, phagocytosis, receptor-mediated 16 What is pinocytosis? Correct Answer: the ingestion of liquid & solutes into a cell by the budding of small vesicles from the cell membrane. How is receptor-mediated endocytosis more selective than regular endocytosis? Correct Answer: Receptor-mediated endocytosis will only bring things into the cell that bind to the receptors on the cell membrane. Endocytosis is random & will bring any solutes into the cell Are LDL and HDL cholesterol or cholesterol carriers? Correct Answer: Carriers What is the mechanism by which cholesterol enters our cells? Correct Answer: Receptor-mediated endocytosis because the LDL receptor is selective to the LDL carrier, therefore only letting the LDL receptor in. When the LDL receptor is in the cell it will bind with a ribosome, separating the cholesterol from the receptor. The receptor will be recycled back up to the membrane. Explain the mechanism of phagocytosis & its importance Correct Answer: 1. A white blood cell will engulf a pathogen with antigens on it 2. A lysosome within the cell will degrade the pathogen resulting in antigen fragments. 3. The cell uses the antigen fragments to make receptors 4. the antigen receptors are put on the cell membrane 17 This is the body's way of alerting other white blood cells of foreign substances What is autocrine signaling? Correct Answer: Cell makes own ligand that binds to a receptor on itself Where is paracrine signaling & name an example Correct Answer: How neighboring cells communicate with each other within the same tissue. An example is inflammatory response & cytokines What is endocrine signaling & how is it a global response? Correct Answer: A cell releases signals (hormones) into the bloodstream so that they affect cells that are a far away What is neural cell signaling & how is it a limited response? Correct Answer: Neuron signals only a couple cells through release of NT What is nexus signaling & provide an example of where this occurs. Correct Answer: Cells signaling through gap junctions, i.e. muscles What is direct contact cell signaling & provide an example Correct Answer: Cells that signal to other cells that are bound to one another through proteins in their membranes. An example is WBC binding to tumor cells 18 Are gap junctions referring to 1 channel or multiple channels? Correct Answer: Thousands of gap junction channels Describe the process of how cells form gap junctions & include connexons & connexins Correct Answer: Each cell has a connexon (hemi channel) made of 6 proteins called connexins. The two connexons come tougher to form a gap junction channel What is positive chemotaxis? Correct Answer: movement of WBCs toward the damaged tissue region because cytokines led them there How does the body create inflammation? Correct Answer: 1. Histamine is released from a cell 2. Histamine causes epithelial cells to form gaps, allowing WBCs to wiggle through them 3. Blood plasma also gets out through the gaps & causes the area to swell (edema) 4. Blood plasma causes redness 5. Pressure from blood plasma pushes on pain receptors What are the signs of inflammation? Correct Answer: 1. Tumor (swelling or edema) 2. Rubor (redness from blood flowing to infected site 19 3. Calor (heat from blood flow) 4. Dolor (pain) Signs of inflammation are the body's way of healing itself, so why do people take antihistamines? Correct Answer: It reduces swelling which reduces pain, but will stop the body's natural response of healing Why do ligands need receptors to enter the cell? Correct Answer: they are either too big or hydrophilic, so they wouldn't get through the membrane. Nuclear and cytoplasmic receptors are intracellular receptors that alter DNA by doing what? Correct Answer: Changing gene expression What are the 3 types of plasma membrane receptors? Correct Answer: 1. Enzyme receptors: ligand binding activates the receptor enzyme activity 2. Ligand-gated (ionotropic): receptor becomes a channel for ions to flow through 3. GPCR: ligand activates 2nd messenger & effector proteins Explain the difference between upregulation & downregulation of receptors? 20 Correct Answer: Upregulation is when a cell makes more receptors to increase its response to substances. Downregulation is when a cell removes receptors from its membrane in order to decrease its sensitivity to substances. What is the difference between kinase & phosphatase? Correct Answer: Kinase (adds phosphate) and phosphatase (removes phosphate) What is signal transduction? Correct Answer: When a ligand binds & creates a cascade of events leading to activation of effector proteins & second messengers Describe the pathway of GalphaS Correct Answer: 1. + AC (effector protein) 2. + cAMP (2nd messenger) 3. + PKA (later effector) 4. Increase in protein phosphorylation (target action) Describe the pathway of Galphai Correct Answer: 1. - AC (effector protein) 2. - cAMP (2nd messenger) 3. - PKA (later effector) 4. Decrease phosphorylation 21 Describe the pathway of Gq Correct Answer: 1. + Phospholipase C (effector protein) 2. + DAG + IP3 (2nd messengers) 3. + PKC & Ca2+ 4. Increase protein phosphorylation & Ca2+ binding proteins What is the function of PDE? Correct Answer: convert cAMP to AMP What are the 3 stages of embryonic development? Correct Answer: Hyperplasia (mitosis), hypertrophy (growth), & differentiation What are the 3 primary germ layers? Correct Answer: ectoderm, mesoderm, endoderm What does the ectoderm give rise to? Correct Answer: skin and nervous system What does the endoderm give rise to? Correct Answer: Internal lining of body What does mesoderm give rise to? 22 Correct Answer: Body cavity membranes, the inside lining of blood vessels (endothelium), connective tissue & muscle What are the 4 primary types of cell tissue? Correct Answer: Epithelial, muscle tissue, nervous system tissue, & connective tissue What is the order that fluid flows at the ateriole end of the capillary? Correct Answer: IVF plasma — ISF—- ICF What is the order of compartments which fluid flows through at the Venus end of the capillary? Correct Answer: This end is for waste dump, so fluid will flow ICF — ISF— IVF plasma What are the 3 types of cell-cell junctions that hold cells together & make up a junctional complex? Correct Answer: Tight junctions, adhering junctions, & desmosome Compare & contrast to roles of tight junctions, adhering junctions (belt) & desmosomes in the junctional complex Correct Answer: Tight junctions help anchor receptor proteins to the cell surface & help regulate solutes in or out of the cell. Belt junctions and desmosomes are for structural support & each have actin filaments that run throughout the cell 23 What is another name for adhering junction? Correct Answer: Belt junction What is the purpose of actin filaments on adhering and desmosome junctions? Correct Answer: Reduces the forces of tearing from each cell because the filaments are spread out throughout the cell What type of integral membrane protein binds cells to connective tissue? Correct Answer: Hemidesmosome